Environmental radioactivity associated with mining in Africa: sources, levels, and health risks–a systematic review

Abstract

This systematic review and meta-analysis evaluated the environmental radioactivity associated with mining operations across Africa. It included 26 studies published between 2010 and 2025. A subgroup meta-analysis revealed that regions impacted by mining exhibit significantly elevated activity concentrations of radionuclides: the weighted averages for Radium-226 (226Ra), Thorium-232 (232Th), and Potassium-40 (40K) were 1097 ± 78.46 Bq/kg, 92.22 ± 8.26 Bq/kg, and 396.98 ± 35.18 Bq/kg, respectively, compared to non-mining regions. Further analysis indicated that phosphate mining areas had the highest 226Ra concentration at 1,653.02 ± 156.45 Bq/kg, 232Th at 150.41 ± 17.00 Bq/kg, and 40K at 360.82 ± 61.77 Bq/kg. In contrast, uranium mining areas showed lower concentrations; 226Ra at 121.88 ± 112.94 Bq/kg, 232Th at 132.40 ± 139.60 Bq/kg, and 40K at 341.40 ± 85.10 Bq/kg, while gold mining regions recorded 226Ra at 427.05 ± 97.17 Bq/kg, 232Th at 53.41 ± 28.32 Bq/kg, and 40K at 394.33 ± 46.38 Bq/kg. Radium Equivalent activity, external (Hex) and internal (Hin) hazard indices, annual effective dose, and Excess Lifetime Cancer Risk (ELCR) were higher in phosphate mining areas (1937 ± 180.39 Bq/kg; Hex = 5.12; Hin = 9.79; effective dose = 1.16 mSv/y; ELCR = 4.16 x 10−3) compared to uranium and gold mining areas. These findings revealed substantial radiological risks in mining regions across Africa, suggesting the urgent need for improved monitoring protocols.